Main.c: In function 'low':
Main.c:7:5: warning: implicit declaration of function 'itoa' [-Wimplicit-function-declaration]
    7 |     itoa(n,str,10);
      |     ^~~~
Main.c:9:9: warning: implicit declaration of function 'strlen' [-Wimplicit-function-declaration]
    9 |     a = strlen(str);
      |         ^~~~~~
Main.c:4:1: note: include '<string.h>' or provide a declaration of 'strlen'
    3 | #include<math.h>
  +++ |+#include <string.h>
    4 | 
Main.c:9:9: warning: incompatible implicit declaration of built-in function 'strlen' [-Wbuiltin-declaration-mismatch]
    9 |     a = strlen(str);
      |         ^~~~~~
Main.c:9:9: note: include '<string.h>' or provide a declaration of 'strlen'
Main.c:13:1: warning: control reaches end of non-void function [-Wreturn-type]
   13 | }
      | ^
/usr/lib/gcc/x86_64-alpine-linux-musl/12.2.1/../../../../x86_64-alpine-linux-musl/bin/ld: /tmp/ccbfnFiG.o: in function `low':
Main.c:(.text+0x8a): undefined reference to `itoa'
collect2: error: ld returned 1 exit status